Apparatus for clarifying liquids and thickening pulps.



H. E. LOWDEN.

APPARATUS POR CLM-Ummm mgums AND THmKBNING PULPS.

APPLIUAI'MN P11411 MAX2? IN2,

1,098,81 2, Patented June 2, 1914.

2 SHEETS-SHEET L 1-1. B. LOWDEN.

APPARATUS FOR CLARIPYiNG LIQUIDS AND THIGKBNING PULPS.

APPLIOATION FILED DHG.27, 1912.

UNITED STATES PATENT OFFICE.

HUGH IB. LOWDEN, 0F DENVER, COLORADO, ASSIGNOR 'TO COLORADO IRON WORKS COMPANY, OF DENVER, COLORADO, A CORPORATION OF MAINE.

APPARATUS FOR CLARII-YING LIQUIDS AND THICKENING PULPS.

To all whom, 1' t may concern:

Be it known that I, HUGH B. LoWDnN,

citizen of the United States, residing at Denver` Colorado, have invented certain new and'useful Improvements in Apparatus for Clarifying Liquids and Thickening Pulps, of which the following is a speo1fication.

My invention relates to an improved apparatus for clarifying liquids and thickening pulps, in which the material is sub]ect ed to quiet settling, the solids subsiding and the clear liquid overflowing continuously, with provision for the removal of the solids in the form of a condensed or thickened pul Tlhe apparatus is adapted to the th1ckening of slimes in the cyanid process of gold extraction, delivering clear solution for precipitation and a thickened pulp suitable for filtration, and to other like separations made in this process; to the settling and collection of kaolin carried in a large relative volume of water and other similar work; and by slight modiication or mode of operation or both, to the separation of pulps into two products, one consisting of the coarser solids and the other of the finer suspended matter or slimes.

For clarifying and thickening on a large scale in the cyanid process simple cones lack capacity, and the flat bottom tanks heretofore in use are defective in the means for moving the settled solids toward the outlet. In round tanks with radial rakes operated from a central vertical shaft, the leverage against which the armsv operate causes frequent breakage, and in rectangular tanks the mechanisms contain vital working parts submerged in the pulp, en failing prohibitive wear, as well as stuiling boxes for transmitting motion to the rakes. l\[ v invention is designed to overcome these defects by providingr means for moving the settled solids to their point of discharge, in which the advantages-of the substantially rectangular tank and rectilinear raking motion are retained,'and no joints subject to wear are submerged in the pulp.

In the drawing forming part of this specification, I have shown a tank of a form similar to that shown in Letters Patent of the United States N0.V976,923 dated November 29, 1910, as the inclined baffles there Specication of Letters Patent.

Application led December 27, 1912. Serial No. 738,925.

Patented J une 2, 1914.

shown are of acknowledged value and the apparatus contains other desirable features.

In my invention the rake consists of a series of transverse blades suitably joined together to move in unison, connected with a mechanism placed without the tank by upwardly extending members through which the motion is imparted toit.

To prevent disturbance of the upper part of the contents of the body of the tank by the motion of the u rights, I surround each of them by a partition or skirt, open top and bottom, forming a space within which such disturbance is confined. These skirts form convenient points of attachment for the ballles.

The desired motion, forward along the bottom of the tank and backward in a plane above the bottom, I secure by means of a crank, which, through a bell crank, imparts these respective motions in proper sequence, the mechanism being susceptible of adjustment as to the distance through which thi.` rake is raised and lowered` and as to the length of stroke, within limits, any increase in vertical motion being at the expense of horizontal motion and vice versa` In the drawing Figure l is a longitudinal vertical section through a thickening tank and shows the 'general relation of the parts; Fig. 2 is an enlarged detail view showing in elevation the operating mechanism; Figs. 3, 4 and 5 are views illustrating further details. Fig. 6 is a view illustratingI the invention as embodied in a classier; Figs. 7 and 8 are views illustrating its embodiment as a conveyer.

The feed enters the tank 1 at the point in dicated by 1", the clear liquid overflows at the opposite end into the launder 2, and the Solids settle, those suhsiding on the Hat portion of the bottom 1l being raked forward into the cone 3, from which they are drawn at ils apex 4, together with the coarser por tion of the solids which settle directly into the cone.

The rake is shown at 5, and the uprights Vwhich extend upwardly and connect with the operating mechanism are indicated at 6 and 6. The motion of the rake being very slow (one cycle in about three or four minutes), there will not'be any appreciable disturbancc communicated to the liquid miX- ture by the rake. Any moving parts are undesirable in the upper layers of the tank contents. however. and for this reason l surround the uprights b v skirts or parti` tions as indicated at T and 7. These skirts would ordinarily consist of sheet inet-al and be secured to the sides of the tank in such manner as to leave a space Within which the disturbance due to the motion of the uprights would he ronlined. The spaces so inelosed \vonld.be some tour or live inehes wide. and the neeessarv length. The skirts extend above the liquid level and d'nvuward to a point from ivliieli any material disturbance will not he roinmunicated to the clear zone near the sui-tare. The baliles of the Rothwell patent referred to, Where used, would be attaehed to these skirts and direc-.tlv to the sides ot the tank where the sides would he the natural points ot' attachment. or the skirts might extend the full length ot the tank` forming false sides. lhese battles are indicated at 31 in Fig. 1.

The rake operatingI mechanism is shown on an enlarged seale in Fig. 2. In this the shaft S has slow rotary motion imparted to it` b v any suitable means, carrying with it the crank 9. Motion is transmitted by erank 9 to the. lever arm 10 through the confleeting rod 11. The upright 6 of the rake is carried by the lever arm 12 which is keyed to the sa me shaft as the lever l0, and forms with it a bell crank journaled on the slider 13. The slider 13 is ot any form adapted to slide on a` guide, as the bar 14, and has upQn it tivo stops 15 and 15 which limit the motion ot the lever arm 10. An arm is shown at .1G Which carries a Weight lll and serves to eounterbail-.mce such portion of the Weight of the, rake as necessary. ln the position shown the slider is represented at. the end of the backward stroke. Assuming the erank ll to revolve, the next movement will be the lowering of the arm 1; and with it the rake. which motion will continue until arm 1U comes against stop 15. whereupon the slider will be drawn tornard to the end of the stroke; that is, unt-il the erank has advanced 180 degrees from the position shown.` The return stroke is produced in like manner, the rake being first. lifted, then pushed back. The stops l5 and 15 ma)v be provided With set screws I5 for adjusting the limits between which the arm 10 is permitted to oscillate, and by means ot' these, set screws the litt of the rake may be increased at the expense of the length of stroke and eontrariivise. Within limits. The horizontal motion is in a truly straivht line, and the vertical motion practicalli so, the curve depending on the length of the arm 1:?. There are four of the sliders and bell cranks, one for each upright, the arm 10 being connected to a like arm by the connecting rod 17. The shaft 8 extends across the tank and carries on its other end another crank similar to il whit-h operates the sliders on the other sido of. the tank. The shafts carrying the arms 10 and 'l` also extend across the tank and the upper extremities ot' the uprights may be tied together.

The normal travel ot the rake would be forward close to th-e bottom ofthe tank, and backward in a plane about tour inehes above the plane of the forna rd stroke, hut to permit its operation in planes above the normal l provide the device shown in Figs. S. -1 and 5. These figures sho the lop ot the upright ll, Fig. 3 boing a vien as seen from the end ol' the tank and Figs. -l and 5 beingr od', the two sides projeeted from Fig. in the usual manner. YWhere. this device is used the shaft. 1S would extend ari-oss the tank and would have connected thereto the arm 12 at its oscillating,r end. ln the upright 6 iS a slot 19. in which a block 2U is adapted to slide vertically. and in this hlork is journaled the shaft 1S. (ln the upright is a rack 2l nneshinplr with a pinion whieh is ktved to the shaftl 18. Also keyed to the shaft; T8 is the ratohet Wheel il?, operated h V the latch lever 24 and held b v a pawl 20 carried by thcblock 20. Each of the four uprights is provided with the slot` and adjacent raek, but only one need have the ratohet. and operatingr latch lever, as this will serve to operate all tour in unison if the shafts 18 are connected by sprocket. wheels and chains, as indicated at 25 in Fig. 1. or bv other suitable means which would cause like rotation in both shafts.

The operation olf the apparatus is follows: The feed of solid matter .suspended in a liquid enters the tank at lf. Fig. l, and pass toward the end at which is the over- HOW launder Q. The veloeit;Y ot the pulp in the tank is ver;v low, owing.r to its great cross section with relation to tho inflow. and the finer solids settle on the flat portion of the bottom, the `grosser solidsy 'mostly snbsidinnr in the inverted cone il. The transverse Scrapers or blades of the rake .1 are spared apart a less distanre than the length ot the stroke., so that material carried forward b v (me, blade on a given stroke Will he caught; by the blade next ahead of it on the tollen'- ing stroke, and thus he advanred toward and into the cone 3, from' the apex l, of which it mallT be Withdrawn by the customaryT methods. The operation of the rake will normallv be with the block Q0 bearing against the ripper end of the slot 19; that is. with the planes of horizontal motion near the bottoni of the tank, but in actual praetiee 1in-- avoidable interferenees with the eontinuous operation of various machines in a plant will occur. Thus, the slime pump or other device used to remove the thiekened pulp from 4 might break down or the outlet 4 might become clogged,A and if a 4number ot' thickening tanks were in use in the plant the diminished flou' of slime due to such,v falureat one of the tanksmight not at once be known. Again, the belt drivting the thickener or the slime pump might break or leave its pulley, and the condition not be discovered until after the `lapse of Some time. Even when such conditions are known it is usually desirable to allow the feed to continue entering the tank until repairs are made, as the entire plant must be kept running and the material must be taken care of. Any of thesecontingencies. will cause an accumulation of solids on the bottom of the tank,and if the rake mechanism is inoperative at the time the solids will become very dense. My emergency lift mechanism shown in Figs.3, 4 and 5 meets such conditions by enabling'the rake to operate in planes above normal, so that it may be started in the uppermost position and be lowered a. notch or two at intervals until the accumulation is ,disposed of, and .normal working resumed. This emergency lift is also a desirable feature when a plant is shut down, as for a holiday or for e x tensive repairs, in which cases the rake.

should be raised before stopping and upon resuming operations lowered gradually, so that the hardened slime can be handled without undue strains.

I do not limit myself to the exact construction shown, as any form of slider in combination with a bell crank or its equivalent Will provide the vertical andhorizontal components of the motion in their proper sequence, and other means mi 4ht be used for providing the emergency lit. Nor do I limit myself to the exact application of the mechanisms herer disclosed. An important application'would be to the separation of relatively coarse, granular solids from very fine solids, when it is desired to separate the coarse for regrinding or other treatment. This is a class of Work performed by socalled sand and slime classifiers, and the adaptation of my mechanism to this purpose would consist in using a shallower tank which would be downwardly inclined toward the slime discharge end in such manner that the hath would occupy but a portion of the tank, and in operatin the mechanism at a higher speed. The eed should then be into the bath and the agitation caused by the more rapid operation would cause the fine solids to remain in suspension and overflow the lower end of the tank with the liquid, the sands being raked out of the bath, up the inclined bottom and over its edge. Such an embodiment is illustrated in Fig. 6 in which 25 designates the body of the classifier having the feed launder 26 and launder 27 for carrying away the slimes, the sands being delivered at Q8. The rake is shown at 29 suspended by uprights 30 from the bell cranks and o erated in the manner hereinbefore descri d. The rake actuating mechanism is also adapted to operate a scraper conveyer which may be either hori- -zontal or inclined, as shown in Figs. 7 and 8. In these figures, 31 designates a ccnveyer trough and 32` a bar or carrying member ,carrying a plurality of blades 33 suspended from bell cranks and actuated as will beobvious. The guides 14 need not be parallel toithe pla-ne of the rake, as in certain appli- 'cationsit might be desirable to have them otherwise. .By a change in the relation of the parts the motion could be reversed, that is to say, ,the action of the rake or of a pluner, should the mechanism be applied to a ceder, would be a pushing one instead of a dragging one.

I claim as my invention:

1. A separating apparatus comprisinga tank, having a submerged discharge outfit for solids a reciprocating rake for moving solids to the point of discharge, means extending through the upper layers of the contents of the tank for imparting motion to the rake, andpartitions surrounding-said motion impartin means to prevent the communication of isturbance by the moving parts to the upper layers of the contents of the tank.

2. A se arating apparatus comprising a tank, a ralie, uprights connected to the rake and extending to the top of the tank, operating mechanism connected to the u per ends of said uprights., and stationary skirts inclosing said uprights.

3. In a tank of the class described, a. vertically depending horizontally reciprocating part depending Withinl the tank, and a parti tion open top and bottom inclosing the upper portion of said part serving to confine the disturbance caused by the moving part.

4. A sand and s lime classifier, comprising a settling and classifying tank, a rake within the tank, a slider,'a bell crank journaled on the slider, means for attaching the rake to one arm of the bell crank, means for communicating motion to the bell crank, and means for limiting the oscillation of the bell crank. A

5. A sand and slime classifier comprising a settling and classifying tank, a rake within the tank, a slider supporting the rake to guide its reciprocating motion` and means carried by the slider for raising the rake at the completion of the forward stroke and lowering it at the completion of the backward stroke.

6. In combination a settling and classifying tank, a slider, a bell crank journaled on the slider, a rake Within the tank supported from the bell crank, means for rocking the bell crank, and means for effecting vertical adjustment of the rake in relation to the bell crank, substantially as described.

T. In combination a settling and classifying tank, a plurality of sliders mounted above the same, rock shafts sup orted by the sliders,` arms projecting lateral y from said rockshafts, a rake suspended from said arms, means foroscillating the rock shaft, and stops for limiting the amount of oscillation 'of the rock shaft.

8. In combination a settlin and classifying tank, a plurality of sli ers supported above the same, rock shafts carried by the sliders, arms extending approximately horizontally from the shafts, a rake suspended from said arms, means connected with the shafts for lcounterbalancing the weight of the rakes, a reciprocating element having connections for oscillating the rock shaft, and means for limiting the amount of oscillation of the rock shaft.

9. In combination a settling and classifying tank, a plurality of sliders supported above the same, rock shafts carried by the -sliders, arms extending approximately horizontally from the shafts, a rake, adjustable means connecting the rake with said arms, a reciprocating element having connections for oscillating the rock shafts, and means for limiting the amount.of oscillation of the rock shaft.

l0. In combination a settling and classifying tank, a slider mounted above the same, a rock shaft journaled in the slider, a rake within the tank, connections between the rake and rock shaft for causing the oscillations of the shaft to raise and lower the rake` -a push and pull device having a connection with said shaft to one side of its axis, and means for limiting the oscillation of said shaft.

In testimony whereof, I aix my signature in presence of two Witnesses.

HUGH B. LoWDEN.

IVi tnesses F. L. MIDDLETON, BENNETT S. JONES.

Il is hereby certifiedA that in Letters Patent No. 1,098,812, granted June 2, 1914, npon the application of Hugh B. Lowden, of Denver, Coloraio, `for an improvement in ,Apparatus for Clarifying Liquids and Thickening Pulp\s,an erroriappears in 'mel-e:

. x munie" read Mza; and that the Said Leners Pat shonld be read with this 00rrecton therein that the same :hay conform to' the record of .the casein the Patent Oice. l A Y Y I i i I Signed and sealed this 7th dayof Jnly, A. VD., 1914. i

[am] R. F. WHITEHEAD,

l Actzng 0f Patents.

o'n l Letters'Paten'tNo. 1,098,812.

Col-rect the printedrspecifieation requiring correction as follows: Page 3, line 86, for the worri i 

